1. Technical Field
The present invention relates in general to the field of computers, and, in particular, to wireless devices. Still more particularly, the present invention relates to an improved method and system for reducing power consumption of a wireless device in a Local Area Network (LAN).
2. Description of the Related Art
Computer networks have greatly enhanced the computing power available to an individual computer by linking the individual computer to other computers and devices. Not only do networks provide for the exchange of information between autonomous computers, but they also enable each “node” in the network to share resources common to the entire network. Each node may be a computer, a data storage area, an output device such a printer or an interface to another network such as the Internet. Through resource sharing, application programs, databases and physical equipment in the network may be made available to any node without regard to the physical location of the node.
There are generally two types of network interconnections for connecting nodes. The nodes in a wired network communicate among themselves by using transmission lines, either electrical or optical, to carry signals between nodes. The nodes in a wireless network, on the other hand, communicate between nodes using radio frequency signals or other types of wireless communication media.
One type of wireless network is a wireless local area network (WLAN). WLAN's typically use high-frequency radio waves carrying digital data to communicate between nodes. Nodes in the WLAN communicate via transceivers at each node. Each transceiver both transmits and receives radio waves containing digital data. All nodes are within relatively close proximity to one another, such as within a building or an educational campus. The proximity of the nodes permits the network to operate reliably at low power and at high data rates. In a WLAN, nodes are typically defined as either an access point or a client device.
An access point is a stationary server computer providing an infrastructure and access point for client devices. That is, the access point coordinates with other access points to control the flow of data between access points and from access points to client devices. Data delivered to the client devices may be from a server on the WLAN, or more typically, from a remote source such as an Internet.
Client devices are typically mobile computing devices such as laptop computers, personal digital assistants (PDA's), etc., which are typically battery powered. While such units may run for several hours if only running a local stand-alone application, transceiving radio signals across the WLAN, such as prescribed by IEEE Standard 802.11b, can double the power requirement of the unit, thus reducing the unit's effective battery life by 50%. When the battery of the client device is effectively discharged, the client device can no longer be used for computing or communicating with the WLAN, and important data and/or work may be lost. A spare battery can be carried with the laptop computer, but this adds additional inconvenience, cost and weight to the total unit. In addition, switching out batteries typically requires the laptop computer to be powered down, which is, at a minimum, an inconvenience, and has a potential consequence of causing the client device laptop computer to be off-line from the WLAN at a mission critical time. Furthermore, a large percentage of the cost and weight of such a mobile computer is taken up by the battery. Accordingly, to reduce battery weight and increase battery life, it is desirable to keep the client device's transceiver power usage and the accompanying battery drain at a minimum.
Therefore, there is a need for a method and system that reduces the power consumption of the battery power client device, while still transceiving data consistently and effectively, and maintaining the client device's wireless connection to the WLAN.